Most Common Lennox® Furnace Error Codes (and What They Mean)

December 06, 2019

While your Lennox® heating system cannot chat with you, it has a process to communicate a furnace error.

Its control panel has twin LED lights that can display a fault code. Depending on the problem, your furnace could show continuous or flashing lights.

Although there are some simple furnace repairs you can do on your own, the majority of fixes are best handled by the professionals. When your heater refuses to kick on or deliver warmth, contact Rapids Sheet Metal Works Inc at 715-301-0256 for skilled furnace repair in Wisconsin Rapids.

Our specialists will swiftly identify and fix the malfunction, even if you don’t own a Lennox heater. We can service any types or makes—and get the comfort reintroduced to your home without delay.


What Does the Flickering Light on My Heating System Mean?

Your heater depends on lights to flash code when it is malfunctioning. It also engages this setup to tell you it’s working like it should.

Correct function includes:

  • Concurrent slow flash—furnace heating correctly.
  • Concurrent fast flash—furnace is initiating the call for heat.

If you notice one light going on and off slowly and the other going on and off quickly, your furnace may have a low flame signal. This can occur even when your heater is operating correctly. It means the flame sensing rod might need to be cleaned or in the incorrect spot on the burner. Call us at 715-301-0256 for support.

Here are some of the most typical faults for Lennox furnaces.

Heating System Will Not Start

Here are a few of the light patterns you could observe when your heating system won’t turn on or keep heating. The bulk of these errors must be repaired by a specialist, like one from Rapids Sheet Metal Works Inc.

  1. The pair of LED lights are off. This indicates your HVAC system might not have electricity. Examine the breaker box to make sure the heating system fuse isn’t flipped. You should reset the fuse if it has moved into the “off” area. If it immediately flips after a subsequent reset, leave the breaker alone and contact us at 715-301-0256.
  2. An individual light is unchanging and the other is flickering slowly. This shows the flame rollout switch is possibly not working right. The switch is an essential safety tool that helps in avoiding fires and carbon monoxide. You shouldn’t seek to fix this issue without professional help.
  3. A single light is flashing quickly and the other is flickering slowly. This likely indicates power polarity has been inverted. Your heating system could have a wiring issue that calls for professional assistance from Rapids Sheet Metal Works Inc.
  4. All lights are flickering slowly. This indicates your heater’s blower motor possibly isn’t operating. This component circulates hot air from the HVAC system into your residence. We can help in pinpointing what’s wrong with this part.
  5. A single light is blinking slowly and the other is flashing rapidly. This indicates your heating system might have insufficient voltage or a short circuit. Get in touch with our specialists at 715-301-0256 for help.
  6. One light is blinking on, on and off while the other flashes on, off, on. This signifies there might be a fault with your furnace’s control board or wiring. Rapids Sheet Metal Works Inc can determine the problem and take care of it.
  7. The pair of lights show alternating slow flashes. This means your furnace likely has a flame failure. There may be a problem with its gas supply, gas valve or ignitor control. Reach out to us at 715-301-0256 for assistance.
  8. A single light flickers slowly while the other remains steady. This often means your heating system’s limit switch is open. The switch keeps your heating system from getting too hot. Call the specialists at Rapids Sheet Metal Works Inc for assistance.

Furnace Blower Works But No Warm Air

Here’s what may be broken when you notice your heater’s blower fan working, but you aren’t receiving any heated air.

  • Both lights are giving alternating rapid blinks. This indicates your furnace ignitor may not be working. This piece kindles gas in your heater to create warm air and should be fixed by an expert from Rapids Sheet Metal Works Inc.

Depend on Us for Skilled Furnace Repair

When you need to have your heating system fixed fast, depend on the professionals at Rapids Sheet Metal Works Inc. Our technicians will repair the fault promptly and have your home feeling comfortable again soon. Reach out to us at 715-301-0256 or contact us online to request an appointment now.